1. Field of the Invention
The present invention relates to a treating instrument inserted into, for example, a body cavity of a patient for medical treatment or into a given cavity of a pipe or duct for treatment or repair.
2. Description of the Related Art
For example, Published Unexamined Japanese Patent Application 56-112221 and Published Unexamined Japanese Utility Model 62-164009 disclose biopsying forceps as one form of a treating instrument for an endoscope. In the forceps disclosed, a pair of openable/closable biopsying cups are mounted on the distal end of a lengthy insertion sheath. The cups are connected to the forward end of operation wire means inserted through the insertion sheath.
The operation wire means is connected at a base end to an operation mechanism on the operator's side of the forceps. In the forceps, biopsying cups are opened and closed by the operation of an operation mechanism on the operator-end side and hence a remote-controlled push/pull operation.
In the conventional treating instrument for an endoscope, an operation force of the operation mechanism is transmitted by operating wire means to the biopsying cups on a distal end of the lengthy sheath. It is necessary to use an operation wire means of a proper thickness enough strong to transmit an operative mechanical drive force to the cups. In the conventional treating instrument for an endoscope, however, there is a limit on the diameter narrowing of the insertion sheath, failing to reduce the diameter of the insertion sheath to a minimum possible extent.
Further, a mechanism is required which can transmit a drive force which arises from the actuated operation wire means, as a mechanical motion, to the treating member, such as the biopsying forceps. This involves a complex structure on the distal end of the insertion sheath.
Since the cups are opened or closed by the manually-controlled operation of the operation wire means, such opening/closing operation appreciably differ from operator to operator. It is thus difficult to accurately open and close the cups.
Further, there is a possibility that, when the insertion section of the treating instrument is to be inserted into a meandering duct or tract, an operation force involved upon the operation of the operation wire means will be partially absorbed, failing to accurately transmit such operation force to the distal end of the insertion section. It is thus difficult to accurately open and close the cups in a desired fashion.